Streptomycetes are Gram-positive bacteria of Actinomycetales. These organisms can produce many economically important secondary metabolites. With the development of molecular biology, gene sequencing technology and synthetic biology, people gained a better understanding of the Streptomyces family. The means to transform genome on the molecular level is also increasing. By simplifying the Streptomyces genome rationally and efficiently, it will improve the yield and quality of the metabolites as well as reduce the consumption of the substrates. Markerless knockout is an important way to carry out genetic modification. Here we describe novel genome modification techniques developed for Streptomyces in recent years with focus on the markerless knockout technologies.
Chromosomes, Bacterial ; genetics ; Gene Knockout Techniques ; methods ; Genes, Bacterial ; genetics ; Streptomyces ; genetics

Objectives To examine the clinical usefulness of magnetic resonance spectroscopy (MRS) on assessment of vascular dementia (VD) in patients with stroke; the relationships between metabolic changes of brain and clinical symptom improvements after giving rivastigmine in these patients.Methods 20 stroke patients without VD, male 17, female 3, with a mean age of (71.7?4.7) years old; 23 stroke patients with VD, male 20, female 3, a mean age of (72.9?5.1) years old; 20 normal volunteers were studied, a mean age of (70.9?4.8) years old. MRS was performed in all these patients. The patients with VD were prescribed rivastigmine hydrogen tartrate ("Exelon", Norvatis), and given MRS assessment half a year later.Results The patients with VD had a significantly lower N-acetyl aspartate/Creatine (NAA/Cr) ratio (mean?SD: left: 0.57?0.30; right: 0.66?0.29) and higher Choline/Creatine (Cho/Cr) ratio (mean?SD: left: 1.79?0.52; right: 1.97?0.44) in bilateral temporal hippocampus area, compared to those without VD (mean?SD: NAA/Cr: left, 0.91?0.31; right, 0.87?0.27, P

Objective:To study the healing effect of Chitin dressing on second-degree scalds in mice and rabbits respectively.Methods:The model of the second-degree scald was established in mice and rabbits respectively by vapour and hot water;the healing time was observed and the tissue specimens were obtained from the scalds for pathologic analysis.Results:Compared with the contrast group,the healing time in chitin dressing treated group was shorter(P

Aim To investigate TY501′s role in bleo-mycin ( BLM )-induced pulmonary fibrosis in rats. Methods Forty rats were randomly divided into 5 groups, including the sham operation, BLM, PFD, TY501(high and low dose) groups. After administra-tion of BLM intratracheally, PFD and TY501 were giv-en in each group daily, according to the dosage de-signed during 21 days. Lung coefficient, PaO2 were tested before killing the rats. The contents of ALB, ALP, LDH, GSH, HYP were detected by regent kit respectively. PCⅢ and COL4 were determined by ELISA. Results ( 1 ) Some indicators of alveolitis in early stage of IPF: the contents of lung coefficient in three treatment groups were lower and PaO2 was higher than those in BLM group ( P<0. 05 ); compared with BLM group, the contents of ALB, ALP, LDH in the treatment groups reduced on 21 st day ( P<0. 05 );the expression of GSH in BLM group was increased for feedback regulation and higher than the treatment groups and the sham operation group (P<0. 05);(2) some indicators of pulmonary interstitial fibrosis in late stage of IPF:the expressions of HYP, PCⅢand COL4 were reduced after the treatment. There were signifi-cant differences compared with BLM group ( P <0. 05 ) . Conclusions TY501 is valuable for the ther-apy of IPF, the same as the positive drug pirfenidone. TY501 attenuates BLM-induced pulmonary fibrosis, which may be related to the affection of TGF-βpathway and inhibition of MMPs.

Objective To investigate the influencing factors of preterm premature rupture of membranes and maternal outcomes. Methods 326 cases with PPRM singleton were selected as the study group in our hospital,and 300 singleton cases with preterm premature rupture of membranes as the control group. Retrospective investigation of the pregnant women and neonatal was performed. Results By single factor analysis,there was no significant difference between the two groups of gestational hypertension,gestational diabetes,uterine dysplasia, uterine scar incidence(P > 0.05);The incidence of reproductive tract infection and fetal abnormalities in study group was higher than that in the control group(P<0.05). The single factor analysis in multivariate logistic regres-sion with statistical difference analysis of reproductive tract infection and abnormal fetal position for preterm prema-ture rupture of the placenta affect independent risk factors. The incidence of neonatal asphyxia and neonatal pneu-monia in the study group was higher than that in control group,and the neonatal weight was lower than the control group,Apgar score was lower than that in the control group(P<0.05). Conclusion the reproductive tract infec-tion and abnormal fetal position of preterm premature rupture of the placenta membranes affect the independent risk factors for preterm premature rupture of membranes ,adverse neonatal outcomes,neonatal asphyxia and the incidence of pneumonia,and light weight need further research.

ObjectiveTo determine the therapeutic effect of Gegentang granules on a disease-syndrome mouse model combining human coronavirus 229E （hCoV-229E） pneumonia with Hanshi Yidu Xifei syndrome in vivo. MethodMice were randomly divided into normal group， infection group， cold-dampness group， model group， chloroquine phosphate group （0.18 g·kg^-1）， interferon-α2b （IFN-α2b） group （1.83×10⁶ U·kg^-1）， Gegentang granules high-dose and low-dose groups （6.6， 3.3 g·kg^-1） with 10 mice in each group. Cold-dampness environment and hCoV-229E infection were used for modeling， and the general status and lung index of mice in each group were observed. The viral load in lung tissue was detected by real-time fluorescent quantitative polymerase chain reaction （Real-time PCR）， the pathological changes in lung tissue were evaluated by hematoxylin-eosin （HE） staining， the levels of serum gastrointestinal hormones and inflammatory factors in lung tissue were detected by enzyme-linked immunosorbent assay （ELISA）， and the percentage of peripheral blood lymphocytes was detected by flow cytometry. ResultComparing with model group， Gegentang granules could significantly alleviate the physical signs of Hanshi Yidu Xifei syndrome， including listlessness， weakness of limbs， sticky stool， etc. Comparing with model group， Gegentang granules high-dose group significantly reduced lung index， histopathological score of interstitial lung and bronchus， and the level of serum motilin （P<0.05， P<0.01）， two doses of Gegentang granules could significantly increase the level of serum gastrin （P<0.05， P<0.01）， the percentage of CD4⁺， CD8⁺ T lymphocytes in peripheral blood （P<0.05， P<0.01）， and the level of tumor necrosis factor-α （TNF-α） in lung tissue was significantly decreased （P<0.01）， and the level of interleukin-6 （IL-6） showed decreasing tendency. ConclusionGegentang granules has therapeutic effect on model mice. It can improve the appearance and behavior characterization， regulate the level of gastrointestinal hormones， decrease lung index and histopathological score， and possibly play an immunomodulatory role by inhibiting the expression of inflammatory cytokines in lung tissue and restoring the percentage of peripheral blood lymphocytes.

Shufeng Jiedu capsules， a Chinese patent medicine composed of Polygoni Cuspidati Rhizoma et Radix， Forsythiae Fructus， etc.， has shown positive effects in the clinical treatment of upper respiratory tract infections， pharyngitis， acute exacerbation of chronic obstructive pulmonary disease （AECOPD）， and coronavirus disease 2019 （COVID-19）. The available evidence suggests that Shufeng Jiedu capsules can modulate the proportions of immune cells and the concentrations of inflammatory cytokines， thereby easing symptoms and enhancing cure rates. The existing reviews predominantly focus on the clinical applications of Shufeng Jiedu capsules， while the comprehensive review of the immunomodulatory effect of this medicine remains to be carried out. This review delineates the immune responses triggered by respiratory tract infections， and then summarizes the clinical application of Shufeng Jiedu capsules and its main chemical components. Principally， this review summarizes the immunomodulatory and anti-inflammatory mechanisms， mainly focusing on various immune cells including macrophages， neutrophils， natural killer （NK） cells， and lymphocytes. In addition， this paper discusses the influences of Shufeng Jiedu capsules and its main chemical components on signaling pathways， secretion of pro-inflammatory cytokines， and antibody production. In terms of innate immunity， the intervention effects of Shufeng Jiedu capsules are highlighted by its capacity to inhibit the activation of nuclear factor kappa-B （NF-κB） and interferon regulatory factor 3 （IRF3） pathways. Additionally， Shufeng Jiedu capsules have been shown to reduce the expression of microtubule-associated protein 1 light chain 3 Ⅱ （LC3Ⅱ）， thereby suppressing the inflammation and autophagy of macrophages. Furthermore， the influence of this medicine extends to altering the proportions of neutrophils and nature killer（NK） cells. Regarding adaptive immunity， Shufeng Jiedu capsules can increase the proportion of T cells in peripheral blood and restore the balance of B cells. This review aims to provide directions for the further research and clinical application of Shufeng Jiedu capsules.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-positive bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-positive bacteria from blood cultures in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:A total of 3 163 strains of Gram-positive pathogens were collected from 51 member units，and the top five bacteria were Staphylococcus aureus（ n=1 147，36.3%），coagulase-negative Staphylococci（ n=928，29.3%）， Enterococcus faecalis（ n=369，11.7%）， Enterococcus faecium（ n=296，9.4%）and alpha-hemolyticus Streptococci（ n=192，6.1%）. The detection rates of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）were 26.4%（303/1 147）and 66.7%（619/928），respectively. No glycopeptide and daptomycin-resistant Staphylococci were detected. The sensitivity rates of Staphylococcus aureus to cefpirome，rifampin，compound sulfamethoxazole，linezolid，minocycline and tigecycline were all >95.0%. Enterococcus faecium was more prevalent than Enterococcus faecalis. The resistance rates of Enterococcus faecium to vancomycin and teicoplanin were both 0.5%（2/369），and no vancomycin-resistant Enterococcus faecium was detected. The detection rate of MRSA in southern China was significantly lower than that in other regions（ χ2=14.578， P=0.002），while the detection rate of MRCNS in northern China was significantly higher than that in other regions（ χ2=15.195， P=0.002）. The detection rates of MRSA and MRCNS in provincial hospitals were higher than those in municipal hospitals（ χ2=13.519 and 12.136， P<0.001）. The detection rates of MRSA and MRCNS in economically more advanced regions（per capita GDP≥92 059 Yuan in 2022）were higher than those in economically less advanced regions（per capita GDP<92 059 Yuan）（ χ2=9.969 and 7.606， P=0.002和0.006）. Conclusions:Among the Gram-positive pathogens causing bloodstream infections in China， Staphylococci is the most common while the MRSA incidence decreases continuously with time；the detection rate of Enterococcus faecium exceeds that of Enterococcus faecalis. The overall prevalence of vancomycin-resistant Enterococci is still at a low level. The composition ratio of Gram-positive pathogens and resistant profiles varies slightly across regions of China，with the prevalence of MRSA and MRCNS being more pronounced in provincial hospitals and areas with a per capita GDP≥92 059 yuan.

ObjectiveBidirectional and two-sample Mendelian randomization（MR） method was used to investigate the bidirectional causal relationship between constipation and pneumonia and to understand the potential relationship between the two diseases from a new perspective， providing new targets for future treatment strategies. MethodConstipation and pneumonia datasets were selected from the genome-wide association study（GWAS） website for the European population in 2021. The data related to constipation included 411 623 samples， and the single nucleotide polymorphism（SNP） data were 24 176 599. The pneumonia data contained 480 299 samples with a number of SNPs of 24 174 646. In this study， inverse variance weighting（IVW） was adopted as the main analysis method of MR， supplemented by weighted median method， simple model， weighted model and MR-Egger regression analysis results， and sensitivity analysis was performed to evaluate the robustness of the results. ResultSeventeen SNPs highly correlated with constipation and 12 SNPs highly correlated with pneumonia were finally included. IVW analysis results of forward MR analysis showed that constipation increased the risk of pneumonia｛odds ratio（OR）=1.143， 95% confidence interval（CI）［1.045， 1.249］， P=0.003｝， MR-Egger regression， simple model， weighted model and weighted median analysis all supported the result（P<0.05）. IVW analysis by reverse MR analysis showed that pneumonia did not increase the risk of constipation｛OR=1.138， 95%CI［0.974， 1.329］， P=0.103｝， MR-Egger regression， simple model， weighted model and weighted median analysis also supported this result. ConclusionThe bidirectional and dual-sample MR analysis method is used to confirm the causal relationship between constipation and pneumonia from the perspective of genetic variation， while there is no obvious causal relationship on the contrary. This study will be helpful for the clinical diagnosis and treatment of constipation and pneumonia， and provide a reference for the study of the pathogenesis between the two.